With development of the data storage technologies, various data storage devices are capable of providing a more powerful data storage capability to a user, and the data access speed is significantly improved. As the data storage capability is improved, the user puts forward higher requirements on the data reliability and response time of the storage system.
Nowadays, there has been developed a technical solution of creating a storage system based on multiple levels of storage media having different access speeds. For example, frequently used data are loaded from a storage device having a lower access speed to a cache device having a higher access speed. Further, the cache is used to respond to an access request from outside of the storage system. The technical solution may improve the data response efficiency to a certain degree. However, the conventional solutions are generally impaired by the problem of being unable to reclaim the cache pages corresponding to the invalid data in the disk.